Heart stimulator utilizing a pressuresensitive semiconductor



Dec. 19, 1967 M M. COHEN HEART STII-ZULATOR UTILIZING APRESSURE-SENSITIVE SEMICONDUCTOR Filed Nov. 18, 1964 AORTA E- 1%? RT.AURIGLE V 7 Zia; 2: l3 1/ LEFT AURICLE 3 PRESSURE l4- TRANSDUCER ,DELAY[-5 CIRCUIT TRICUSPID j.- VALVE -swncnms j: i I I RT. VENTRICLE 1. 1 L5'I 3 LEFT vENTRlcLE- ELECTRODE '1'. l9

07c. POWER '7 SOURCE 5 I6 I6 I i I I I 0.0. POWER PRESSURE DELAYSWITCHING fi SOURCE TRANSDUCER CIRCUIT CIRCUIT SOURCE l/VVE/VTOR MARVINM. COHEN B) W I 6-! J: 9, ATTORNEYJ.

United States Patent 3,358,690 HEART STIMULATOR UTILIZING A PRESSURE-SENSITIVE SEMICONDUCTOR Marvin M. Cohen, Silver Spring, Md., assignor toUnited States of America as represented by the Secretary of the ArmyFiled Nov. 18, 1964, Ser. No. 412,268 3 Claims. (Cl. 128-419) ABSTRACTOF THE DISCLOSURE A heart stimulator in which a pressure-sensitivetransducer,-such as a tunnel diode -is placed within the walls of anauricle in the heart. When a high pressure condition is reached, aswitching signal is transmitted to a switching circuit, after beingdelayed, and a DC power source is activated thereby activating anelectrode placed in the ventricle.

This invention relates to a heart stimulator. More particularly, thisinvention relates to an ingenious electronic system for stimulating theheart in order to effect pumping of blood in tune to the need put on thecirculatory system.

Of fairly recent vintage are electronic systems for heart stimulation,known as Pacemakers. The known Pacemakers work in an ingenious manner tostimulate the ventricle, either the right or left ventricle, or both, inorder to provide necessary stimuli in the event that heart blockage hasatrophied normal nerve ends in the muscle walls of the heart.

It is well known that nodes of nerve endings are situated on the atriumportion of the heart, being located on the right auricle and leftauricle. In effect, these nodes act as pressure transducers,continuously telemetering pressure changes in the auricles so that asthe pressure increases, the tricuspid valve between the right auricleand right ventricle, and the mitral valve between the left auricle andleft ventricle, are opened and the appropriate ventricles suck in theblood from their respective auricles and pulse out the blood throughtheir respective pulmonary artery and aorta. In other words, as pressureis built up in the atrium, nerve endings and nerve networks in the wallof the heart lead to suitable nodes in the ventricle portion of theheart to dispose of the blood in suitable pressurized fashion. Eventhough the heart reacts to the pressure change as telemetered from theatrium to the ventricle, the ventricle itself has a natural beat.

Some congenital heart defects are of a type resulting in what is knownas a blockage. In such instances the naturally performing telemeteringoperation mentioned in the preceding paragraph is in malfunction so thatthe heart operates inefiiciently. The newly developed Pacemakers takeover the telemetering function to an extent by provid ing the ventriclewith suitably spaced pulses of electrical energy as if, in fact, thenerve networks of the heart were delivering such pulses. Unfortunately,the prior art Pacemakers leave much to be desired inasmuch as theyproduce a constant pulse frequency, not variable to the requirements ofthe individual. In other Words, the Pacemaker, in delivering itselectrical pulses does so at a beat ordinarily prevalent when theindividual is at repose. In the event the individual is engaged instrenuous activity requiring a greater quantity of blood, the Pacemakerdoes not operate on a faster rate, but actually fights the individual inhis additional requirements for blood flow. On the other hand, when theindividual is asleep, the Pacemaker does not decrease its frequency, butmaintains a constant rate, thereby producing a greater flow of bloodthan is necessary and oftentimes prevents the individual from obtainingrestful sleep.

Accordingly, the primary object of the present invention I 3,358,690Patented Dec. 19, 1967 is to provide a unique telemetering systemresulting in heart stimulation accounting for variances in the need forblood supply.

It is another object of the present invention to disclose an electricalsystem utilizable in a heart stimulation program.

It is yet another object of the present invention to proide a heartstimulator which is extremely compact and is efficient in operation.

Additional objects and advantages of the present invention will becomeapparent upon a more detailed consideration as set forth below and takenin conjunction with the drawings, wherein:. 7

FIGURE 1 is a diagrammatic cross-section of the heart in the diastolephase; and,

FIGURE 2 is a block diagram of the circuitry involved in carrying outthe present invention.

Now, turning our attention to FIGURE 1, it will be noted that thecross-sectional view represents a diagrammatical view of a mammalianheart, and in particular the heart of a human being. It will be assumedthat the heart will have undergone a degree of heart blockage, whichnecessitates the implantation of the present invention. Within the wallsof the right auricle and/ or the left auricle, a tiny transducer 11 ispositioned. This tiny transducer is merely a pressure sensitive element,such as a tunnel diode which, under present day technology, may beconstructed to assume an extremely tiny dimension. The pressuretransducer 11 is positioned in the walls of the heart near the innerperiphery by means of open heart surgery, now nicely perfected by ourmedical scientists. Tiny leads 12 emerge from the heart and are carriedoutwardly through the parietal pleura of a power source such as a DC.batery 13. The DC battery provides suitable biasing to the tunnel diodepressure transducer when such is utilized.

The pressure transducer selected is such that it may be sensitive topressure changes of the type found from low pressure to high pressureconditions in the atrium. When a high pressure condition is achieved inthe atrium, the pressure transducer senses it and would ordinarily throwa suitable electronic switch immediately. However, by means of lead line14, the switching is delayed by means of a conventional delay circuit 15before it is connected to the conventional switching circuit 16 throughlead line 17. When the switching circuit is phased to the on side, thepower source 18 is put into the line leading to an electrode 19 throughleads 20 and 21. The electrode 19 is of the same type as employed in aPacemaker and is of an extremely small size.

It will be appreciated that as in the same manner or use of aconventional Pacemaker, the electronic circuitry and power source may bepositioned outside the body or may be located directly below the skinand outside of the sternum. Such parts of the circuitry would, ofcourse, be the power source 13, the delay circuit 15, the switchingcircuit 16, and the power source 18.

By positioning the electronic components in this manner and employingtiny leads to the heart, there is practically no discomfort to theindividual utilizing this system. The entire arrangement is very smalland the power consumption is almost infinitesimal, so that the circuitryof the present system may be removed for the replacement of either theelectronic components or the power source, which may be in the form ofbatteries, by means of a simple operation which may be performed on anannual basis.

In FIGURE 2, a further rendition of the circuitry of the presentinvention is set forth, showing the DC. battery source 13, the pressuretransducer 11, the delay circuit 15, the switching circuitry 16, the DC.power source 18, and the electrode 19. Electrode 19 is positioned in theventricle portion of the heart, either right or left, or both.

By means of the present invention, it will be seen that technologicaladvances have been made to take the place of damaged heart conditionsand that the circuitry involved is, in fact, analogous to the heartcircuitry, at least in the function thereby achieved.

It will be apparent that many changes and modifications of the severalfeatures described herein may be made without departing from the spiritand scope of the invention. It is, therefore, apparent that theforegoing description is by Way of illustration of the invention ratherthan limitation of the invention.

What is claimed is:

1. A heart stimulator, comprising:

(a) a pressure sensitive transducer means adapted to be inserted in theatrium of a heart for sensing a high pressure condition in said atrium;

(b) electrode means adapted to be inserted in the ventricle of saidheart; and

(c) telemetering means connecting said transducer and said electrodemeans, said telemetering means comprising a delay circuit, a switchingcircuit, and a DC power source, said delay circuit being connected toreceive the output of said pressure sensitive trans- References CitedUNITED STATES PATENTS 3,184,972 5/ 1965 Sikorski 7 3-698 3,240,207 3/1966 Barker 128-205 3,253,596 5/ 1966 Keller 128421 FOREIGN PATENTS1,067,538 10/ 1959 Germany.

RICHARD A. GAUDET, Primary Examiner.

W. E. KAMM, Assistant Examiner.

1. A HEART STIMULATOR, COMPRISING: (A) A PRESSURE SENSITIVE TRANSDUCERMEANS ADAPTED TO BE INSERTED IN THE ATRIUM OF A HEART FOR SENSING A HIGHPRESSURE CONDITION IN SAID ATRIUM; (B) ELECTRODE MEANS ADAPTED TO BEINSERTED IN THE VENTRICLE OF SAID HEART; AND (C) TELEMETERING MEANSCONNECTING SAID TRANSDUCER AND SAID ELECTRODE MEANS, SAID TELEMETERINGMEANS COMPRISING A DELAY CIRCUIT, A SWITCHING CIRCUIT, AND A DC POWERSOURCE, SAID DELAY CIRCUIT BEING CONNECTED TO RECEIVE THE OUTPUT OF SAIDPRESSURE SENSITIVE TRANSDUCER, SAID SWITCHING CIRCUIT BEING CONNECTED TORECEIVE THE OUTPUT OF SAID DELAY CIRCUIT, AND SAID DC POWER SOURCE BEINGADAPTED TO BE CONNECTED TO SAID ELECTRODE MEANS BY SAID SWITCHINGCIRCUIT WHEN SAID SWITCHING CIRCUIT IS ACTIVATED BY THE DELAYED SIGNAL